Wireless receiver



vApril 28, 1942. J. A. vAN LAMMEREN WIRELESS RECEIVER Filed July 22, 1959 INVENTOR. .l0/MNM? ,4. f4/V Hm/IHREN BY 7% ATTORNEY.

Patented Apr. 28, 1942 2,281,468 A wlRELEss RECEIVER' Johannes Antonius van Lammeren, Eindhoven, Netherlands, assignor, by mesne assignments, to Radio Corporation of America., New York, N. Y., a corporation of Delaware 4 Application July 22, 1939, Serial No. 285,896 In the Netherlands July 23, 1938 3 Claims.

Wireless receivers capable of being automatically tuned to a number of predetermined stations by means of a station selector constituted by a dial, a key-board or similar device in which a position disc mounted on a shaft to rotate with friction is provided for each of said stations are known per se. 'I'he said position disc generally exhibits at its circumference a change in profile by which a member associated with the disc concerned is governed, said member operating the motor which actuates the tuning means, such as the tuning condensers. The stopping time of this motor is thus determined by the position of the said change in prole. This position relatively to the shaft can be altered by rotation of a position-disc relatively to the shaft, which therefore has the result that if by operating a station selector, such as a press-button, tuning toa given station were automatically effected originally, operating the same station-selector after rotation of the position disc on its shaft has the effect of tuning to another transmitter. 'I'he adjustability of the position-discs is important for the user of the set. The adjustment of one of the position-discs should, however, not have the effect of altering the adjustment of the other position-discs since the possibility of correct automatic tuning of the other stations would naturally be imperilled thereby. Unless they are very complicated the constructions already known are not sufhciently proof against this.

The arrangement according to the invention allows by simple means to ensure that altering the position of one of the position-discs has not the effect of altering in any way the adjustment of the other position discs relatively to the shaft on which they are mounted.

The wireless set according to the invention is characterized in that all of the position-discs are axially forced against a stop by one common spring, the discs of each pair of discs having arranged between them a 4plate which cannot be rotated relatively to the shaft, said plates being capable of transmitting axial pressure between the two adjoining discs. 'I'he axial pressure which is exerted by the common spring brings about between all the plates and intermediate discs a normal pressure which, when normally the shaft on which the plates and discs are mounted rotates, is high enough for all the plates and discs to follow integrally the rotation of the shaft. If, on the contrary, one of the positiondiscs is held in position while the shaft is rotating, the position-disc held in position slips between tlie adjoining plates whereas all the other plates continue to rotate at the speed of the shaft; thus the desired altering of the adjustment of the position-disc concerned can therefore be obtained without the adjustment of the other position discs varying in any way with respect to the shaft.

In one form of construction of the device according to the invention each of the plates arranged between the position discs is furnished with a key fitting into a key-track on the shaft and this ensures that the various plates cannot be rotated.

In a further form of construction of the set according to the invention the discs have arranged between them diaphragms which are resilient axially and which have their central part secured to the shaft. In a preferred embodiment the central parts of these diaphragms are clamped between the end surface of a number of sleeves pushed on the shaft and clamped together.

In order that the invention may be clearly understood and readily carried into eiect it will now be described more fully with reference to the accompanying drawing.

In the drawing accompanying this specification, Fig. 1 illustrates an embodiment of the invention using keyed disks; Fig. 2 illustrates another embodiment of the invention using clamped resilient disks; and, Fig. 3 is a plan view of one of the disks shown in Fig. 2.

Fig. 1 shows one form of construction in which a shaft I carries four position discs 2, 3, 4 and 5. These position discs are engaged by feeders 6, 1, 8

and 9 respectively which, when the runways ex- Y tending onthe position discs pass from one active level to the other, stop by their resultant movement the motor which operates the tuning members, or give the operator a palpable indication that the correct tuning position is reached. Systems of this kind are already known per se. A suitable arrangement is disclosed in U. S. patent application Serial No. 233,188, filed October 4, 1938. It often occurs that one position disc is to be moved from one given tuning position to another. For this purpose, the disc has to be rotated relatively to the shaft I, it being naturally necessary to take care that the other discs should mainain their correct original position since otherwise the tuning would be imperilled by the other discs. According to the invention, this is ensured by arranging between the position discs plates I0, II, I2, I3 and I4 which, due to the fact that they have a projectingv portion which extends into a key track in the shaft i, cannot rotate relatively to the shaft I. The aggregate of the friction plates and theposition discs is locked between a shoulder I6 of the shaft I and a press plate I1. This press plate is engaged by a helical spring Il which is kept stressed by a nut 20 via a press member I9. Each of the plates is thus capable of transmitting the axial pressure necessary for the friction between its two adjoining position discs. For the sake of completeness, Fig. 1 shows in addition the further arrangement of the tuning members with their driving members. 'Ihe shaft I carries at one of its ends a gear wheel 2| which engages a pinion 23 drivn by the motor 22.- Further on the shaft cleairance (rotation) between the diaphragms and the shaft does not occur in any way, which would only be possible by very accurate nishing of the parts shown in Fig. 1. Moreover, the constructionshown in Fig. 2 issubstantially simpler than that shown in Fig. 1.

I claim:

1. In a shaft adjusting instrumentality, a rotatable control shaft. a series of substantially similar sleeve members mounted over said shaft in spaced axial relation, a plurality of control I carries a pinion 24 which engages a gear wheel 25 which in turn is mounted on the rotor shaft 26 of the tuning condenser. v The condenser can be driven manually by coupling, for example, to the motor shaft a gear wheel which is mounted on the shaft of a tuning knob.

In the embodiment shown in Fig. 2 the d iscs of `each pair of position-discshave arranged between them -a diaphragm 21 which is slightly resilient in the axial direction. (In Figs. 1 and 2 similar parts are designated by like reference numerals.) They have their central part clamped between sleeves 2l and their parts arranged outwardly to a further extent are located between the position-disc III, II, I2 and I3. This also permits of giving one of the position-discs a different position relatively to the shaft I without the other position-discs losing their original position. Fig. 3 is a front elevation of suena diaphragm. the part 29 forming the central part which is clamped between the sleeves 28, the outer edge ill being resilient in axial direction due to the slots 3| and also due to the fact that these diaphragms are made from thin sheet material. The thickness and hardness of the material is such that the friction' torque of the discs can be readily released. The advantage of this construction over that shown in Fig. l resides in the fact that the diaphragms can be made and arranged in such manner that cam discs one for each of said sleeves, each of said cam discs being rotatably mounted on its respective sleeve member and so that each sleeve forms a hub for its cam disc, a plurality of thin resilient spacing diaphragms interposed between adjacent sleeve. members, clamping means for clamping said sleeve members and said diaphragms to the control shaft whereby said shaft, sleeve members, and diaphragms rotate as a unit upon rotation of said shaft. said diaphragms being extended radially so as toact as spacers between adjacent cam'discs, and resilient means for resiliently clamping together said spacing diaphragms and cam discs.

2. The arrangement described in thenext preceding claim characterized by that said cam discs comprise I-section discs whereby each of said cam discs comprises, in effect, a disc provided with two opposltely extending flanges, each disc having a thickness along that portion which includes its two flanges which is substantially the same as the lengthof the sleeve member associated therewith ,whereby said cam discs are in contact with the associated diaphragms only in the vicinity of the periphery thereof.

3. The arrangement described in claim 1 characterized by that each of said diaphragms is formed as a thin disc having a plurality of substantially coaxial slits for increasing the axial resilience of the diaphragms. 

